PropertiesLauncher creates a ClassLoader that is used by the Launcher
to load an application’s classes. During the creation of this
ClassLoader URLs from its ClassLoader. This resulted resulting in Java
agents that are added to the system class loader via the -javaagent
launch option being available on both the system class loader and the
created class loader. Java agents are intended to always be loaded by
the system class loader. Making them available on another class loader
breaks this model.

This is the same problem that was in ExecutableArchiveLauncher and
that was fixed in ee08667e (see gh-863).

This commit updates PropertiesLauncher so that it skips the URLs of
any Java agents (found by examining the JVM’s input arguments) when
copying URLs over to the new ClassLoader, thereby ensuring that Java
agents are only ever loaded by the system class loader.

Closes gh-4911

Closes gh-4942

Add ExitCodeExceptionMapper strategy interface which can be used to map
exceptions to exit codes.

Closes gh-4803

Previously, the default launch script would send SIGTERM once and then
wait for up to 60 seconds for the app to have stopped. If the service
was stopped immediately after being started the first SIGTERM would
occasionally be ignored (presumably because the JVM was not yet in a
state to handle it) causing the service stop request to fail.

This commit updates the launch script to resend SIGTERM to the process
if it's still running 30 seconds after the first SIGTERM was sent.

Closes gh-4941

$arguments needs to be split on spaces so it can’t just be wrapped
in quotes. This commit updates arguments to be an array that is then
expanded ("{arguments[@]}"). The use of @ and double quotes means that
it is expanded into all elements individually quoted.

See gh-4866

This commit completes the changes to consistently used static final
fields for Log instances that were started in ec2f33f9. Specifically it:

 - Removes this. when accessing logger fields that are now static
 - Renames some fields from log to logger
 - Makes some logger fields static

See gh-4784

SecurityFilterAutoConfiguration uses SecurityProperties which uses
SessionCreationPolicy from spring-security-config. This commit makes
SecurityFilterAutoConfiguration conditional on SessionCreationPolicy,
thereby preventing a startup failure if spring-security-web is on the
classpath but spring-security-config is not.

Closes gh-4919

This commit adds a suit of integration tests for the launch script. See
the accompanying README.adoc for further details.

Closes gh-4872

81a47639 introduced a regression when multiple RUN_ARGS or JAVA_OPTS were
configured. Rather than the JVM being launched with multiple arguments
all of the RUN_ARGS or JAVA_OPTS were passed as a single argument. This
caused unexpected behaviour and typically caused the application to fail
to start.

This commit updates the quoting of the arguments the are supplied when
launching the app using start-stop-daemon so that space-separated
entries in RUN_ARGS and JAVA_OPTS remain separate.

Closes gh-4866

Previously, the launch script used which to determine the availability
of start-stop-daemon. which isn’t available by default on all OSs.
For example, it’s not available by default on CentOS 5.

This commit updates the launch script to use type when determining if
start-stop-daemon is available. This improves the portability of the
script and makes the use of type consistent throughout the script.

Closes gh-4925

Previously, the launch script would wait for the pid file to exist
before continuing. This didn’t work 100% of the time as it left a 
window where the file had been created but the PID had not been written
to it that could result in an incorrect report of the app failing to
start.

This commit updates the script to wait for the file to have a size
greater than zero before continuing. This ensures that the pid has
been written to the file before the pid is read from the file and used
to check that the process is running.

Closes gh-4923

Closes gh-4932

Update SpringApplication to publish an ExitCodeEvent when a valid exit
code is known.

Fixes gh-4804

Update exit code support to allow the ExitCodeGenerator interface to
be placed on an Exception. Any uncaught exception implementing the
interface and returning a non `0` status will now trigger a System.exit
with the code.

Fixes gh-4803

Closes gh-4821

* pr/4831:
  Fixed the check whether Log4j2 is available on the classpath

In Spring Boot 1.3.1 the class 'org.apache.logging.log4j.LogManager'
is used to check which logging backend is in use. But this class is
part of the log4j-api.jar and not part of the log4j-core.jar.
That means the check is invalid, as it does not detect the actual
core implementation of Log4j2 correctly.

When you want to redirect Log4j2 logging via SLF4J, a NPE occurs
each time the application is reloaded by the devtools, because the
class Log4j2RestartListener tries to shutdown Log4j2 resources.
This is done by accessing some internal shutdown method via
reflection. The method that is being looked for does not exist
when the log4j-api.jar is available only on the classpath,
resulting in a NPE. This causes the application to stop,
disappearing from the Spring Boot Dashboard in Eclipse

Closes gh-4831

Closes gh-4847

Issue #4533 was supposed to make BasicBatchConfigurer public again but
unfortunately only the class visibility was changed. This commit makes
sure it can be overridden.

Closes gh-4888

Update the Oomph instructions.

Closes gh-4844

* pr/4867:
  Fix invalid port number in doc

Closes gh-4867

By type is too restrictive and surprising for users who wanted to add their
own MetricReaderPublicMetrics for other reasons.

Closes gh-4839

# Conflicts:
#	spring-boot-autoconfigure/src/main/java/org/springframework/boot/autoconfigure/websocket/WebSocketAutoConfiguration.java

Tomcat's websocket support requires Java7 or later. That commit makes
sure to register its support only when such requirement is met.

Closes gh-4846

Clarify that "spring.config.*" properties doesn't work in configuration
files.

Closes gh-4838